The present invention relates to a navigation system. More specifically, the invention relates to a system for giving route guidance to a walker, using a portable terminal.
There is provided a navigation technique using a three-dimensional map display for displaying on a display screen a projection plane obtained when a three-dimensional map is seen from an arbitrary viewpoint, so as to implement a navigation system that is intuitively obvious. This technique is disclosed in JP-A-2003-232639, for example. When a navigation apparatus with the three-dimensional map display is implemented, it sometimes happens that a map component to be noted is hidden behind other map component, depending on the position of a viewpoint. For this reason, information that a user wishes to know, such as a current position, a destination, or a route connecting the current position and the destination is not sometimes displayed on the display screen. The publication described above aims to provide a map display device and the navigation apparatus that have implemented the three-dimensional map-display cap able of displaying information on the map component hidden from the other map component, using the technique disclosed in the publication.
As another method of implementing the intuitively obvious navigation system, there is further provided a technology referred to as “Mixed Reality” technology, in which a CG (Computer Graphic) image for navigation is superimposed on an actually photographed image of a real world, for display.
Further, there is disclosed a technique in JP-A-11-108684, in which the image of a landscape in a traveling direction of a vehicle is picked up by an image pick-up camera mounted on a nose or the like of the vehicle, and navigation information elements are superimposed on the image of the landscape in the background by an image synthesis unit, for display. This technique aims to cause a driver to more intuitively grasp the current position and the traveling route of the vehicle than in a case in which the driver depends depending on a graphic display alone.